This creates intermediate file Makefile.SDUX,
based on Makefile.PL in the current directory,
and writes Makefile by executing Makefile.SDUX.
The resulting Makefile contains a modified target clean and a new target depot,
so that you can only follow with

make; make test; make depot

The target depot will install the module in the sdux subdirectory,
writes module.psf and invokes swpackage.
Thus certin privileges are required for this target.